Peugeot 207 no acceleration

[paulgregory10]

Hi all hope someone can help trying to sort out a 207 1.4 petrol with no acceleration for a friend

Vin no VF3**************[VIN obfuscated, can be read by forum staff]

Need a wiring diagram for tps and app have used diabox to get codes p0221 and p0121

Using diagbox actuator test to check motorised butterfly valve result in no movement of butterfly valve.

Display shows pedal movement but nothing at throttle any thoughts would be greatly appreciated thanks

[GiveMeABreak]

Ok, so here is the main injection diagram, followed by teh Accelerator posistion sensor and the motorised throttle.

There are 2 tracks on the accelerator position sensor and they are compared with each other to ensure the data is correct. As per your fault codes there is a discrepancy between the two readings. This usually means a new accelerator pedal as the sensor unit is inside. However in this case the part (1601V8) is no longer available from Peugeot. So you will have to look for a second hand one.

1261: accelerator pedal position sensor /
1262: motorised throttle

Your Fault Codes:
P0221: Motorised butterfly signal track 1 and 2 not coherent fault
P0121: Motorised butterfly signal fault, non coherence of signals 1 and 2



Details of the component wiring and location:

Motorised Throttle

Location

Wiring:
1372: Throttle motor command by -
1371: Throttle motor command by +
1220: throttle potentiometer supply 5V
1219: throttle potentiometer position signal 2
1367: motorised butterfly potentiometer earth
1218: throttle potentiometer position signal 1

Accelerator Position Sensor

Location

Wiring

1377: Accelerator pedal 1 position info
1379: accelerator pedal position earth
1378: Accelerator pedal 2 position info
1380: + 5 volt accelerator pedal position indicator power supply
731B: accelerator pedal point of resistance / signal

[paulgregory10]

Thank you Marc as always you are a star would the faulty pedal not allow diabox to perform an actuator test on the motorised butterfly?

[GiveMeABreak]

I can't remember exactly what tests you can do, but there are many and if none are in the standard parameter tests then you should be able to select your own personalised tests from those available.

As you can see there are 2 tracks of info (from the accelerator pedal sensor and the motorised throttle), so there is data coming from them or it wouldn't be reporting the discrepancy fault - it's just that the data tracks when compared don't match up or the data from one track is corrupt.

[ozvtr]

PP shows accelerator pedal is good. You can’t really test it any other way, as it uses Hall Effect Sensors. The accelerator pedal assembly tends to be very reliable anyway.

If the engine ECU shows throttle position errors, it won’t move the butterfly until those codes are cleared.


I have a blurb here
https://citroenc3owners.com/tips-for-a- ... t4411.html
on the VDO powered throttle body assembly. FYI.

It's possible that there was a "glitch" in one of the potentiometer signal paths. It's also possible that glitch has cleared. In which case you might not find a fault. The very first thing that I would do is clear the codes and try the throttle again. If it fails, then there is a "hard" fault that you can track down. If it runs properly, then there was a temporary fault and you might not find anything wrong. But still check for corrosion in the electrical connectors (see below).

You can check the resistance of the potentiometers by measuring across pins 1 and 2 and 1 and 6, then 5 and 2 and 5 and 6 of the throttle’s electrical connector. Move the butterfly backwards and forwards while you check the resistance. However, again, the carbon tracks tend to be very reliable.
My bet is on corrosion in the electrical connectors. Check for corrosion on the electrical connectors of BOTH the throttle and the engine ECU. The connections are in Marc's diagrams.

If you track the fault to the throttle and you pull the throttle apart, you may be able to clean or inspect the carbon tracks of the potentiometer, or the wiper arm (if they are the problem).

As Marc says, the outputs of the two potentiometers must agree or the engine ECU shuts the throttle down. However just because the engine ECU doesn't receive a signal from one of the potentiometers, that doesn’t mean that there is a fault with the potentiometer!

[paulgregory10]

Thanks for all the info I suspect wiring at the pedal as I do get a fluctuation on diabox. going to rewire the pedal connection tomorrow as I have got another pedal and it shows the same fault. I am getting readings from the throttle body potentials on pins 1&2 and 5&6 will update then thank you

[paulgregory10]

I have cleared the codes but they return immediately suggesting a hard fault as suggested over will let you know how I get on thanks

[paulgregory10]

Have changed accelerator pedal no change and redone all the connections still track 2 error, then changed throttle body and remade all connections still track 2 error voltage doesn't match on diabox still.
I have stopped out the ECU which will clear the track 2 error and will now match the voltages on track 1 and 2. So it would appear the fault lies in the ECU itself. Need to get it repaired if anyone knows HOW?

[ozvtr]

I have stopped out the ECU

I don't know what that means. Did you mean swapped?

Have you checked the electrical connectors for corrosion? You really don't want to go down the path of repairing/replacing the ECU.

[paulgregory10]

Yes swapped the ecu to check in diabox for throttle readings which we now get a matched signal but can't start the car obviously as bsi and keys don't match

[ozvtr]

Are you sure you have checked for corrosion on pins C1, C2, C3 and C4 of the maroon connector of the engine ECU? Particularly C2 and C3?
Have you tried plugging the original ECU back in?

You really want to eliminate EVERYTHING before you suspect the engine ECU. Changing/repairing it is a total 8@ll ache!

[paulgregory10]

Yes OZVTR I will check the pins again on row c as you suggest and the original ecu is back on fault is still there thanks I have also checked for shorts on the cable between each wire and ground of the App and Tps.

[ozvtr]

the original ecu is back on fault is still there

That's a pity. Looks like it's the engine ECU. They are usually pretty reliable.

What's your next step going to be?

[paulgregory10]

Ok latest update thanks to all for the help. I purchased a second hand ecu same hardware and software versions of j34p Ecu then swapped over the EEPROM from the original ECU, so the immobiliser would work and this has now fixed the car.
Many thanks to Marc and OZVTR

[ozvtr]

swapped over the EEPROM from the original ECU, so the immobiliser would work and this has now fixed the car.

That's hard core! Was the EEPROM potted or conformal coated?
Congratulations, good work!